avcodec/lpc: zero the middle odd sample in the output

Signed-off-by: James Almer <jamrial@gmail.com>

libavcodec/lpc.c

@@ -53,6 +53,7 @@ static void lpc_apply_welch_window_c(const int32_t *data, ptrdiff_t len,
             w_data[i] = data[i] * w;
             w_data[len-1-i] = data[len-1-i] * w;
         }
+        w_data[n2] = 0.0;
         return;
     }
 

libavcodec/x86/lpc.asm

@@ -37,7 +37,7 @@ SECTION .text
 %macro APPLY_WELCH_FN 0
 cglobal lpc_apply_welch_window, 3, 5, 8, data, len, out, off1, off2
     cmp lenq, 0
-    je .end
+    je .end_e
     cmp lenq, 2
     je .two
     cmp lenq, 1
@@ -104,7 +104,7 @@ cglobal lpc_apply_welch_window, 3, 5, 8, data, len, out, off1, off2
 
     add lend, (mmsize/4 - 1)
     cmp lend, 0
-    je .end
+    je .end_o
     sub lenq, (mmsize/4 - 1)
 
 .scalar_o:
@@ -135,6 +135,10 @@ cglobal lpc_apply_welch_window, 3, 5, 8, data, len, out, off1, off2
 
     sub lenq, 2
     jg .loop_o_scalar
+
+.end_o:
+    xorpd xm3, xm3
+    movlpd [outq + off1q*2], xm3
     RET
 
 .even:
@@ -233,7 +237,7 @@ cglobal lpc_apply_welch_window, 3, 5, 8, data, len, out, off1, off2
 .one:
     xorpd xm0, xm0
     movhpd [outq], xm0
-.end:
+.end_e:
     RET
 %endmacro